Heat exchanger and method of making same

ABSTRACT

A heat exchanger and method of making same is provided and such heat exchanger comprises a plurality of tubes arranged in parallel relation and a plurality of planar fins each having integral tubular collars extending therefrom which engage and are supported concentrically around the tubes with the collars extending from each planar fin being defined by a first set of collars extending in one direction and a second set of collars extending in a direction opposite from the one direction. The fins are fixed against the tubes in substantially parallel relation with the first set of collars of one fin adjoining and cooperating with the second set of collars of an immediately adjacent fin to provide a precise spacing between fins along the tubes.

United States Patent [191 Siemonsen HEAT EXCHANGER AND METHOD OF MAKINGSAME [75] Inventor: Frederik A. Siemonsen, Richmond,

[73] Assignee: Reynolds Metals Company,

Richmond, Va.

22 Filed: Dec. 19, 1973 21 Appl. No.: 426,320

[52] US. Cl. l65/15l;--165/l76; 165/182 [51] Int. Cl. F28f l/22 [58]Field of Search 165/151, 182,176, 175,

[56] References Cited UNITED STATES PATENTS 1,521,880 1/1925 Guarino165/151 1,834,070 12/1931 Parkinson 165/175 1,898,713 2/1933 Carrier eta1. 165/151 2,994,123 8/1961 Kritzer 165/151 3,256,593 6/1966 Whitney 129/1573 A 3,468,009 9/1969 Clausing 29/1573 B 3,507,026 4/1970 Collins29/1573 B 1 June 17, 1975 3,631,922 1/1972 Ponziani 165/1 51 FOREIGNPATENTS OR APPLICATIONS 460,063 l/1937 United Kingdom 165/151 1,104,9794/1961 Germany 165/182 Primary Examiner-Manuel A. Antonakas AssistantExaminer-James D. Liles [57] ABSTRACT A heat exchanger and method ofmaking same is provided and such heat exchanger comprises a plurality oftubes arranged in parallel relation and a plurality of planar fins eachhaving integral tubular collars extending therefrom which engage and aresupported concentrically around the tubes with the collars extendingfrom each planar fin being defined by a first set of collars extendingin one direction and a second set'of collars extending in a directionopposite from the one direction. The fins are fixed against the tubes insubstantially parallel relationwith the first set of collars of one finadjoining and cooperating with the second set of collars of animmediately adjacent fin to provide a precise spacing between fins alongthe tubes.

' 6 Claims, 4 Drawing Figures HEAT EXCHANGER AND METHOD OF MAKING SAMEBACKGROUND OF THE INVENTION Tube and fin type heat exchangers are incommon use throughout industry and in general it is preferred that thefins therefor be made of comparatively hard metallic materials makingsuch fins less susceptible to damage yet without impairing their heattransfer capabilities. However, it has been found that with fins made ofhigh temper aluminum alloys, such as H-l9 temper, that any tendency toform integral collars above a certain height in such fins results infrequent cracking of collars whereby the fin is generally unsatisfactoryfor use in a heat exchanger.

It has also been found that with H-l9 aluminum alloys ranging inthickness from 0.010 inch to 0.002 inch it is not commercially practicalto make integral tubular collars therein for fin-stacking purposes withsuch collars being of substantial height, generally in excess of 1/1 6inch, for example, whereby it is necessary to resort to dead soft orpartial tempered metal which increases cost substantially.

SUMMARY This invention provides an improved tube and fin type heatexchanger, and method of making same, wherein the fins may be made ofH-l9 temper aluminous materials having a thickness ranging from 0.010inch to 0.002 inch and such heat exchanger may be provided with doublethe spacing distance between immediately adjacent fins than was possibleheretofore yet at a comparatively small cost. The heat exchangercomprises a plurality of tubes arranged in parallel relation and aplurality of planar fins each having integral tubular collars extendingtherefrom which engage and are supported concentrically around saidtubes with the collars extending from each planar fin being defined by afirst set of collars extending in one direction and a second set ofcollars extending in a direction opposite from said one direction. Thefins are fixed against said tubes in substantially parallel relationwith the first set of collars of one fin adjoining and cooperating withthe second set of collars of an immediately adjacent fin to provide saiddouble spacing distance between fins along the tubes in a precisemanner.

Other details, uses, and advantages of this invention will be readilyapparent from the exemplary embodiment thereof presented in thefollowing specification, claims, and drawing.

BRIEF DESCRIPTION OF THE DRAWING The accompanying drawing shows presentpreferred embodiments of this invention, in which FIG. 1 is a sideelevation illustrating one exemplary embodiment of the heat exchanger ofthis invention;

FIG. 2 is a perspective view of a typical fin comprising the heatexchanger of FIG. I particularly illustrating integral collars definedtherein and with such fin being drawn with an exaggerated thickness;

FIG. 3 is a fragmentary view drawn to an enlarged scale with parts incross section and parts broken away particularly illustrating the mannerin which the fins of the heat exchanger of FIG. 1 are stacked inposition with respect to their associated tubes, and

FIG. 4 is an enlarged fragmentary cross-sectional view taken essentiallyon line 44 of FIG. 3.

DESCRIPTION OF ILLUSTRATED EMBODIMENT Reference is now made to FIG, 1which illustrates one exemplary embodiment of the heat exchanger of thisinvention which is designated generally by the reference numeral 10 andcomprises a pair of oppositely arranged header assemblies shown as a topassembly 11 and a bottom assembly 12. The heat exchanger 10 also has aplurality of tubes 13 arranged in parallel relation between the headerassemblies 11 and 12 and a return conduit 14 which will be described inmore detail subsequently. The heat exchanger 10 of this example has atemperature control valve 15 which may be of any suitable knownconstruction and the valve 15 is particularly adapted to receive a fluidsuch as a liquid through a suitable inlet 16 thereof and if the liquidneeds to be cooled it is diverted by the valve 15 into the headerassembly I l and flows through the tubes 13 into the header assembly 12.The liquid from the header as sembly 12 is conveyed by the returnconduit 14 to the valve 15 and exits the valve through a suitable outlet17 thereof.

The valve 15 has a temperature control element (not shown) of knownconstruction and operation which operates to divert fluid flow from theinlet 16 of the valve 15 directly to its outlet 17 in the event that thetemperature of the liquid is such that it does not require cooling andas is well known in the art whereby the valve 15 has its temperaturecontrol element and associated internal passages which cooperate toassure operation of the heat exchanger 10 as described above. It willalso be appreciated that the effective flow area of the return conduit14 is such that it offers less flow resistance than the combined areasof the tubes 13.

The header assemblies 1 1 and 12 are of known construction and includecomparatively large, volume chambers 18 and 19 respectively therein; andthe tubes 13 have opposite end portions 20 and 21 suitably fixed to suchheader assemblies in a fluid-tight manner utilizing any technique knownin the art so that a fluid to be cooled by the heat exchanger 10 willflow under pressure into and out of the'heat exchanger and its componentvalve 15 with no leakage. For example, the ends 20 and 21 may be brazed,welded, or mechanically swayed to their respective assemblies 11 and 12while assuring unobstructed flow communication with the integralchambers of such assemblies.

The heat exchanger 10 has a plurality of planar fins each designatedgenerally by the reference numeral 22 and as seen in FIG. 2, each fin 22has one set or a first set 23 of integral tubular collars extending inone direction; i.e., upwardly, from the plane of the fin and another setor a second set 24 of integral tubular collars 7 extending in adirection opposite from the one direction, i.e., downwardly, from theplane of the fin. For convenience and easy discription thereof, each ofthe tubular collars regardless of whether it extends upwardly ordownwardly is designated by the same refer ence numeral 25. The collars25 and the remainder of the body of each fin 22 are made as a singlepiece construction.

As seen particularly in FIG. 3, the fins 22 are fixed against the tubes13 in substantially parallel relation with the first set 23 of collars25 of one fin, such as the lowermost fin shown at 26 in FIG. 3,adjoining and cooperating with the second set 24 of an immediatelyadjacent fin, shown at 27, to provide a precise spacing (indicated at 30in both FIGS. 3 and 4) between the lower fin 22 and such adjacent fin22. Indeed, the stacking of the fins 22 along the entire length of thetubes 13 is such that two sets of collars of each pair of immediatelyadjacent fins cooperate to provide the precise substantially largespacing 30 between fins.

The integral tubular collars 25 provided in each fin 22 are arranged ina plurality of parallel rows, see FIG. 2, each designated generally bythe reference numeral 31; and, the collars in a particular row 31 arearranged so thatthey alternate in opposite directions perpendicular tothe plane of the fin, i.e., one collar 25 extends upwardly followed byanother collar 25 which extends downwardly, followed by another collarwhich extends upwardly, etc. It will also be seen that the collars 25 inan immediately adjacent pair of parallel rows 31 are arranged instaggered relation so that each collar 25 of the central 'row 31, forexample, has its center arranged approximately one half the distance 33between the centers of a pair of collars 25 in a near row 31 with suchdistance being measured parallel to such row.

Each of the collars 25 has an outwardly flared terminal end portion 35,as shown in FIG. 4, and such outwardly flared end portion 35 enables thecollar to be more easily slid along its associated tube 13 and inparticular' enables easier sliding of the inside surface 36 of suchcollar along the outside surface 37 of the tube 13. The flared endportion 35 is flared on a generous arc or radius 38 as viewed in crosssection; and, the base of the tubular collar 25 is also blended with themain body of the fin on a generous are 39 as viewed in cross section andthe arcs 38 and 39 assure that the tubular collar 25 is formedsubstantially without stress concentrations. It will also be appreciatedthat the collars 25 may be formed using any suitable technique andpreferably are formed first by punching small openings in the fin" stockat each location where a collar is to be formed and then simultaneouslyforming the collars 25 by cooperating punches and dies actingsimultaneously.

The fins 22 may be fixed in position using any suitable technique andpreferably such fins are fixed in position by expanding or forming eachtube 13 radially outwardly a controlled amount so that its outsidesurface 37 is mechanicallyfirmly engaged against an associated collar 25by engaging the inside surface 36 thereof. The tubes 13 and fins 22 maybe fixed together after the opposed ends of the tubes are fixed to theheader assemblies 11 and 12 or such tubes, fins, and header assemblies11 and 12 may be fixed together in one operation by using appropriatefixtures. One technique which may be employed, for example, is to use apencil-like tool having bulbous head which is moved axially through eachtube 13 once the tubes 13 have been fixedinposition in their headerassemblies; and, as the tool head is passed along the full length of thetube 13, it permanently mechanically radially expands the tubes 13outwardly with their outside surfaces 37 firmly against the insidesurfaces 36 of the collars 25.

The preferred thickness range of the fins was given previously hereinand such fins may be used with tubing having any desired outsidediameter. In one application of this invention, /8 inch O.D. tubing wasused with inch spacing between the centers of the tubes 13 in each rowand inch spacing between each immediately adjacent pair of rows; and, asindicated at two locations 40 in FIG. 2. However, it will be appreciatedthat any suitable tubing size and spacing may be used depending upon theapplication of the heat exchanger 1 As previously indicated, the fins 22are preferably made of an aluminum alloy having an H-l9 temper and suchfins 22 may be used with copper tubing, aluminum tubing, or any othermetal tubing used in the art to make heat exchangers. Preferably,aluminum tubes 13 are made of either ll00 or 3003 aluminum alloy andwhen aluminum tubes are used the fins are'made of 7072 aluminum alloy.In heat exchangers which have tubes made of copper the fins arepreferably made of 1100 alloy.

While present exemplary embodiments of this invention, and methods ofpracticing the same, have been illustrated and described, it will berecognized that this invention may be otherwise variously embodied andpracticed within the scope of the following claims.

What is claimed is:

1. A heat exchanger core assembly comprising a plurality of tubesarranged in substantially parallel relation and a plurality of fins madeof an aluminous material having an I-I-l9 temper, each of said finscomprising a substantially planar sheet and two sets of tubular collarswhich are integral with said planar sheet and which engage and aresupported concentrically around said tubes, one of said sets of tubularcollars extending in one direction substantially perpendicular to theplane of said planar sheet and the other of said sets of collarsextending in a direction opposite to said one direction, said fins beingfixed against said tubes in a relation wherein the plane defined by eachsaid planar sheet is substantially perpendicular to the longitudinalaxis of each of said tubes with the said one set of collars of one saidfin adjoiningand cooperating with the said other set of collars of animmediately adjacent fin to provide a spacing between said one andimmediately adjacent fin.

2. An assembly as set forth in claim 1 in which each of said collars hasan outwardly flared terminal end portion which enables easier slidingthereof along its associated tube for fin-stacking purposes.

3. An assembly as set forth in claim 1 in which each of said fins has athickness ranging roughly between 0.010 inch and 0.002 inch.

4. An assembly as set forth in claim 1 in which said collars arearranged in a plurality of parallel rows and immediately adjacentcollars in each row extend in opposite directions.

5. An assembly as set forth in claim 4 in which said collars in animmediately adjacent pair of parallel rows are arranged in staggeredrelation.

6. An assembly as set forth in claim 4 in which said collarsin each rowhave an equal spacing therebetween, said parallel rows have said equalspacing in a direction perpendicular thereto, and the collars in a rowimmediately adjacent another row are staggered roughly one-half waybetween the collars in said other I'OW.

1. A HEAT EXCHANGER CORE ASSEMBLY COMPRISING A PLURALITY OF TUBESARRANGED IN SUBSTANTIALLY PARALLEL RELATION AND A PLURALITY OF FINS MADEOF AN ALUMINOUS MATERIAL HAVING AN H-19 TEMPER, EACH OF SAID FINSCOMPRISING A SUBSTANTIALLY PLANAR SHEET AND TWO SETS OF TUBULAR COLLARSWHICH ARE INTEGRAL WITH SAID PLANAR SHEET AND WHICH ENGAGE AND ARESUPPORTED CONCENTRICALLY AROUND SAID TUBES, ONE OF SAID SETS OF TUBULARCOLLARS EXTENDING IN ONE DIRECTION SUBSTANTIALLY PERPENDICULAR TO THEPLANE OF SAID PLANAR SHEET AND THE OTHER OF SAID SETS OF COLLARSEXTENDING IN A DIRECTION OPPOSITE TO SAID ONE DIRECTION, SAID FINS BEINGFIXED AGAINST SAID TUBES IN A RELATION WHEREIN THE PLANE DEFINED BY EACHSAID PLANAR SHEET IS SUBSTANTIALLY PERPENDICULAR TO THE LONGITUDINALAXIS OF EACH OF SAID TUBES WITH THE SAID ONE SET OF COLLARS OF ONE SAIDFIN ADJOINING AND COOPERATING WITH THE END OTHER SET OF COLLARS OF ANIMMEDIATELY ADJACENT FIN TO PROVIDE A SPACING BETWEEN SAID ONE ANDIMMEDIATELY ADJACENT FIN.
 2. An assembly as set forth in claim 1 inwhich each of said collars has an outwardly flared terminal end portionwhich enables easier sliding thereof along its associated tube forfin-stacking purposes.
 3. An assembly as set forth in claim 1 in whicheach of said fins has a thickness ranging roughly between 0.010 inch and0.002 inch.
 4. An assembly as set forth in claim 1 in which said collarsare arranged in a plurality of parallel rows and immediately adjacentcollars in each row extend in opposite directions.
 5. An assembly as setforth in claim 4 in which said collars in an immediately adjacent pairof parallel rows are arranged in staggered relation.
 6. An assembly asset forth in claim 4 in which said collars in each row have an equalspacing therebetween, said parallel rows have said equal spacing in adirection perpendicular thereto, and the collars in a row immediatelyadjacent another row are staggered roughly one-half way between thecollars in said other row.